By now you will have gotten your
answer as to whether that was a good growing egg or not!
In my experience, after 7 days, I have always been able to see a the little heart fluttering - it looks like a little black smudge that flitter flutters in rhythm. If you didn't see that, or even a much darker mass that moves in response to handling, then I have always found them to be dead eggs. I make a habit of checking at 7 days and again, if I find some questionable ones, again at 11 or 12 days and then I remove the ones that are not developing. I've had rotten eggs explode on me and 0% of people want that experience.
Here is my opinion on handling incubating eggs. I've watched our runner ducks hatch out their own batches in the duck house, and the mama builds a big old volcano style nest, with layers of eggs. She routinely gets up, juggles eggs around, scoots them with her beak, and then settles on the rearranged stack. I have a hovabator that I use that has a fan but no egg turner, so 3 times a day, up until I stop turning them 3 days before hatch, I lift the lid and rustle them around gently. The incubator loses a degree or 2 in heat, but I have always had at least a 75% hatch rate. The same, from my observation and cleaning out of the duck house post hatch, that my lady runners enjoy.
I think 75% is good. Other's might think higher is better. I have just tried to watch what the mama's do and mimic it. I use my bare hands, no gloves or anything. The only thing I've noticed that is VERY important is the humidity factor. Lower humidity means tough eggs and poorer hatch rate. I keep my incubator at 60% humidity all the time until 3 days prior to hatch and then I just fill all the trays and make it nice and damp in there.
Curious how it turned out for you! How exciting! I have a good batch in the incubator right now, and they will be peeping in about 2 weeks. So far, 95% of them have had living babies so we will see how many survive the last 2 weeks and hatching.